Bug or Not with thumbnails?

[Skettalee]

I have cleared all my thumbnails and been rereading everything in the help file about the thumbnails section of settings and was trying to recreate the thumbnails but I have tons of folders of icon files that no matter what setting I change around and even highlighting and CNTRL + ALT + F5 to refresh the icons but now its no longer showings all the icons and i know the files still have the icon image in them and it still shows them in windows explorer. I know there are a great deal of options you can change around to display the icons or have them behave different but I dont understand what it is that I have checked or not checked that's keeping them from displaying now. I tired restarted the computer, the app and even moved some of the icons to a newly made folder and they aren't showing still anymore.